1. Field of the Invention
The present invention relates to a method for allowing a control of a vehicle provided with at least two wheels in case of puncture of a tyre.
2. Description of the Related Art
A wheel for a two- or four-wheeled vehicle generally comprises a rim coupled with a tyre that is inflated to a given operating pressure.
Said tyre generally comprises a carcass structure having at least one carcass ply and at least one annular reinforcing structure associated with the carcass ply, a tread band of elastomer material applied to the carcass structure at a radially external position, a belt structure interposed between the carcass structure and the tread band and a pair of sidewalls at axially opposite positions on the carcass structure.
In tubeless tyres, the tyre airtightness is ensured by the radially internal layer of said carcass structure generally referred to as “liner”. In use, due to the natural air leakage through said liner (which in any case is never perfectly impervious to air), pressure within the tyre decreases so that the vehicle's driver is forced to carry out a periodical restoration of said pressure.
In an attempt to make the tyre pressure substantially constant over a rather long period of time, use of rims internally housing a tank containing a fluid under pressure (such as air, nitrogen or other substantially inert gases) has been suggested, in which tank there is a pressure higher than the operating pressure of the tyre. By means of one or more valves suitably operated, the required pressure is restored when needed.
U.S. Pat. No. 4,067,376 shows an alarm system connected with the pressure in a tyre which comprises a pressure-sensitive device susceptible of being mounted to the wheel and suitable to emit sonic or ultrasonic signals each time the inner pressure of the tyre exceeds a maximum value or is lower than a minimum value. Also shown is a system for automatically reintroducing the air lost by a tyre while a vehicle is running, to minimise the effects of a burst. Manufacture of the wheel involves the presence of an integrated annular bag suitable to store an amount of compressed air under high pressure. A safety pressure valve is placed between said bag and the tyre and is adapted to release air from the bag to the tyre each time pressure in the tyre goes down below a predetermined limit.
Patent application WO 03/057515 discloses a wheel assembly for vehicles wherein pressure and temperature inside the tyre are measured at a predefined frequency, and the detected values are transmitted to a processing unit located on the vehicle.
The processing unit, depending on said detected values, selectively causes a fluid connection between the inside area of the tyre and a tank containing pressurized gas and rotationally fixed to the wheel rim, thereby maintaining the desired pressure and temperature inside the tyre.
Patent application Us 2004/0008107 discloses a tyre blow-out detector which is provided with a pressure variation sensor and a transmitting module connected thereto.
When a variation of the tyre pressure is detected, a signal (for example, a HF signal) is transmitted to an on-board apparatus, which alerts the driver of the possible blow-out.